Robert Downey Jr. Welcomes Tom Hiddleston to Instagram by Teasing Him About Taylor Swift

Credit: Jon Furniss/WireImage

Robert Downey Jr. welcomed his on-screen nemesis and real-life friend Tom Hiddleston to Instagram in a way that only he could. Despite being a little late to join, Hiddleston was greeted by friends and fans with open arms on Tuesday--most notably (and sarcastically) by his Marvel co-star.

Downey Jr., who plays Tony Stark (aka Iron Man) alongside Hiddleston's Loki in the Marvel Avengers franchise, poked a bit of good-natured fun at Hiddleston's high-profile romance with pop princess Taylor Swift.

"Join me in welcoming the biggest T. Stark fan of them all to Instagram! @twhiddleston" Downey Jr. captioned a photo of Hiddleston wearing an "I T.S." tank top at the beach during Hiddleswift's epic Fourth of July weekend in Rhode Island. The shirt is, of course, a shoutout to his lady love, but Downey Jr. understandably couldn't resist teasing his friend.

As for Hiddleston's first post on the popular photo sharing app? The handsome Brit teased the return of his character Loki, whom he will play once again in the upcoming movie Thor: Ragnarok. "He's back!" the actor wrote along with a selfie of himself in costume.

RELATED: Tom Hiddleston Joins Instagram--See His Surprising First Post

We're looking forward to plenty more selfies and maybe some retaliation from Hiddleston in the future.